Three-dimensional display (stereo display) to provide stereoscopic display using parallax between the two eyes has gained attention recently. A known image display apparatus has a three-dimensional function that converts a two-dimensional display image into a three-dimensional display image in order to provide a three dimensional display in accordance with the two-dimensional display image. As opposed to this apparatus, another known image display apparatus has a frame rate conversion function that converts a frame rate of an image in order to increase image quality when a moving image is displayed.
Typically, an image display apparatus providing the three-dimensional display has both the frame rate conversion function and a three-dimensional conversion function. FIG. 17 is a block diagram illustrating the configuration of a known image processing device included in the image display apparatus that provides the three-dimensional display. The image processing device 90 of FIG. 17 includes an input selection unit 91, a frame rate converting unit 92, a three-dimensional converting unit 93, and a time base converting unit 94. The frame rate of an input image of the image processing device 90 is 60 Hz, and the frame rate of an output image is 120 Hz.
In a two-dimensional display mode, the input selection unit 91 outputs the input signal to the frame rate converting unit 92. The frame rate converting unit 92 outputs the input signal without any change added thereon as an original signal. The frame rate converting unit 92 also performs a frame rate conversion process on the input image through motion compensation, and outputs a resulting interpolated image. In a three-dimensional display mode, the input selection unit 91 outputs the input signal to the three-dimensional converting unit 93. The three-dimensional converting unit 93 performs a three-dimensional conversion process on the input signal using a motion vector, and outputs resulting left-eye image and right-eye image. The time base converting unit 94 outputs the original image and the interpolated image, output from the frame rate converting unit 92, or outputs the left-eye image and the right-eye image, output from the three-dimensional converting unit 93, in synchronization with display timings thereof.
With reference to the present invention, Patent Literature 1 describes a video signal processing device that selectively perform a process of outputting a three-dimensional display image without any change added thereon, and a process of outputting a two-dimensional display image with a frame rate thereof converted. Patent Literature 2 describes a stereo video generation method configured to detect a motion vector of an image, configured to estimate depth information of the image using the detected motion vector, and configured to perform a three-dimensional conversion process in accordance with the estimated depth information.